Technical Field
The present invention relates to a method of producing a nickel-cobalt composite hydroxide and a method of producing a positive electrode active material for a non-aqueous electrolyte secondary battery.
Description of the Related Art
In recent years, with the miniaturization of electronic devices such as cellular phones, and increasing demand for these devices, secondary batteries as a power source for these electronic devices are required to have higher energy density. Non-aqueous electrolyte secondary batteries, such as lithium ion secondary batteries, are expected to meet such a demand. For the positive electrode active material of a lithium ion secondary battery, a lithium transition metal complex oxide having a layered structure, such as lithium cobalt oxide, lithium nickel oxide, and lithium nickel cobalt manganese oxide, is used.
Examples of methods of producing a nickel-cobalt composite hydroxide, which is a precursor for the above-described lithium transition metal complex oxide, include a coprecipitation method. Japanese Patent Application Publication No. JP 2011-116580 A describes a method of producing a nickel-cobalt composite hydroxide including coprecipitating an additional element with nickel, cobalt, and manganese in a solution containing nickel, cobalt, manganese, so that the additional element is uniformly present in the interiors of the secondary particles of the nickel-cobalt composite hydroxide.